People are increasingly exposed to information these days, often through mobile devices such as portable digital assistants (PDAs). A snapshot of our modern society is likely to reveal many people using mobile devices while performing their daily routine tasks. For instance, people often text, conduct telephone calls, check messages, search the Internet, etc. while performing activities such as walking down the street, driving in their cars, eating in a restaurant, attending meetings, etc. Using mobile devices in such a manner may raise any of a variety of concerns, namely safety and/or etiquette.
In an effort to address such concerns, companies are developing devices that are capable of delivering content to users in an unobtrusive and/or hands-free manner. For example, Google Inc. has developed Google Glass®, which is a wearable computer that provides an optical head-mounted display (OHMD). Google Glass® enables a user to communicate with the Internet using natural language voice commands. In another example, Motorola Mobility Inc. has developed the H19txt Bluetooth® headset, which reads text messages that are received by a mobile device to a user who wears the headset. For instance, the headset may enable the user to receive the text messages automatically without picking up the mobile device.
However, such devices may not be effective and/or socially accepted in some environments. For instance, critics have raised concerns that Google Glass® may be used to invade the privacy of others, for example, by recording people without their consent. Moreover, Google Glass® may not operate effectively in a brightly lit environment. The effectiveness of some devices, such as the Motorola H19txt Bluetooth® headset, may be substantially compromised in noisy environments. Other devices may use tactile communication techniques in an effort to avoid such issues. However, even those devices may be relatively ineffective in some environments, such as environments that involve substantial motion (e.g., vibration). For instance, a construction worker who is operating a jackhammer likely will not feel tactile signals from such a device due to the vibration of the jack hammer.